<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <script type="text/javascript">
      function bodyonload() {
        var canvas=document.getElementById('test');
        var ctx = canvas.getContext("2d");
        ctx.fillStyle = 'green';
        ctx.fillRect(150, 50, -151, 50); // left at -1
        ctx.fillStyle = 'red';
        ctx.rect(150, 100, -151, 50); // left at -1
        ctx.fill();
        ctx.fillStyle = 'blue';
        ctx.fillRect(150, 150, -150, 50); // left at 0
      }
    </script>
  </head>
  <body onload="bodyonload();">
    <canvas id="test" width="200" height="200"></canvas>
  </body>
</html>

